Recently, with the rapid development of smart projection technologies, projection systems with excellent picture quality have rapidly gained a large share of the market. Here, the projection system, also known as a projector, refers to a device that projects images, text, or video onto a curtain or a wall.
The projection system is mainly realized by an “Optical Machine”. The light source of the optical machine mainly comes from incandescent lamps, LED lights, and lasers. No matter what kind of light source is utilized, however, a lot of heat may be emitted in the process of generating light. The lens of the optical machine is more prone to thermal expansion and contraction, and thus a slight deformation thereof may occur. As a result, the lens of the optical machine may lose focus if it operates for a long-term. If the lens of the optical machine operates out of focus, an image presented on a screen may be blurred. At this point, it is necessary to adjust a focal length of projection again so that the image becomes clear.
At present, in order to reduce the deformation of the lens of the optical machine caused by the thermal expansion and contraction, a shell of an all-metal structure and a full-glass lens instead of a resin lens are generally used in a high-end projector. Although this is beneficial to the heat dissipation of the lens of the optical machine to reduce the deformation thereof, the cost of the projection system will be greatly increased.